The present invention relates generally to a material analyzing apparatus and method for measurement of density, segregation (i.e., non-uniformity), and moisture content of a test material.
The invention relates to a material segregation and density analyzing apparatus and method to analyze density and segregation of a material. In particular, the invention relates to a material segregation and density analyzing apparatus and method to analyze at least one of density and segregation of asphalt.
Ninety-six percent of all paved roads and streets in the United states, almost two million miles, are surfaced with asphalt. Asphalt is a relatively low cost pavement material, especially in comparison to other pavement materials, such as concrete. Another asphalt feature that makes it superior to concrete for pavement is its flexibility. The maintenance of asphalt is also typically less expensive than maintaining concrete.
It is the nature of asphalt pavement to be non-uniform. It is very difficult to achieve a non-segregated and completely homogeneous asphalt mix for pavement. Also, the asphalt mix is very difficult to apply in an essentially uniform pavement layer. Therefore, the pavement is characterized by measurements in material variations and/or segregation. These variations or segregation are often visible on the pavement surface, however, it is a very subjective and difficult process for quantifying the pavement segregation amount. Pavement segregation is representative of pavement density.
Segregation can be defined as the separation of coarse and fine aggregate particles in the hot mix asphalt mixture. Alternately, segregation has been described as a separation and consolidation of the larger aggregate asphalt particles, which leave the asphalt mass and rise to the surface of the mix. This segregation can occur in the mixed material before it is fed onto the highway or it may become segregated as it is being placed onto the road surface. Research indicates that segregation has a direct impact on the long-term performance of the asphalt pavement by increasing the air void content of the mix, thus increasing the potential for moisture damage, raveling, cracking and a total disintegration of the affected road surface. Therefore, it is desirable to determine the pavement segregation.
When paving a particular highway, the asphalt mix, which is to be applied is routinely checked for mix properties at the asphalt mix plant. The check attempts to verify the asphalt mix integrity and homogeneity, and thus to control the ultimate density of the asphalt mix, when applied and rolled. The check of the asphalt mix can be correlated to resultant pavement density and segregation when applied. Accordingly, pavement specimens for control can be available for potential density device calibration or referencing of pavement density indicator devices.
When an asphalt paver lays a layer of asphalt mix for compaction on a highway, the asphalt quality will relate to the longevity of the new highway. Such longevity-influencing factors include, but are not limited to, density of the asphalt mix as it becomes compacted on a road surface and the homogeneity and segregation of the asphalt mix. Although the mix of liquid asphalt and rock aggregate segregation may have been ideal at the asphalt plant, there is no guarantee of the mix quality as applied to the road surface. The lack of homogeneity can be described as segregation.
Paving material (pavement) is typically laid down by a paver at about 75% of its desired compaction. During subsequent compaction, for example by being rolled over, it is very desirable to compact the paving material close to the final desired pavement compaction degree, without altering the segregation. The pavement compaction should be as close to the desired compaction to provide an absence of material variations, such as, but not limited to, air voids, which are believed to create defects in the resulting paved structure.
The level of pavement compaction cannot be readily determined without complicated measurements. These complicated pavement measurements may not be accurate. In the past, these complicated pavement measurements typically involved boring out of a portion of the rolled pavement (hereinafter also referred to as xe2x80x9cextractionsxe2x80x9d) and measuring their density in the lab. This process forms a hole in the pavement, which of course is not desirable. This hole is not desirable as the integrity of the pavement is breached.
In order to address these asphalt-related problems, various complicated asphalt pavement measurement systems and devices have been proposed and developed. For example, and in no way limiting of the invention, measurement of pavement dielectric properties has been proposed to determine pavement density, which has been suggested as an indicator of pavement compaction level.
One such known pavement density indicator device is disclosed in U.S. Pat. No. 3,784,905 to Blackwell. The Blackwell device appears to measures dielectric properties of the applied and rolled asphalt, in which the dielectric properties are believed to be representative of a change in pavement or asphalt density. The Blackwell device appears to operate at low frequencies where its operations are subject to variations in moisture and temperature, and thus can result in errors. While Blackwell may provide adequate operations in some instances, the Blackwell device must be moved at extremely slow speeds across the material being tested to obtain a density reading. Thus, it appears that the Blackwell device may need extended time periods of operation to provide a density determination, which as discussed above is not desirable. Further, the Blackwell device possesses a large weight, which may necessitate large supportive objects to support and transport the Blackwell device. The large objects may be dragged across the applied pavement surface, thus potentially causing damage to the often freshly-applied pavement.
Another potential disadvantage of the Blackwell device may be its limited depth adjustability for measurement. This limited depth adjustability may be attributed to the Blackwell electrodes only varying a depth of measurement by changing the height of the electrodes. This electrode configuration is not desirable due to the limited depth adjustability for measurement.
Another known pavement indicator device comprises a nuclear source, which is used to determine density of a pavement material. This nuclear-sourced device has a variety of drawbacks. Some of these drawbacks in the nuclear-sourced devices include that the nuclear-sourced device requires a licensed operator, controls, and a radiation shield (e.g., a lead enclosure). Of course, these nuclear-sourced device drawbacks lend to an increased cost of the nuclear-sourced device, increased cost of operation, and inherent dangers found with nuclear materials. Further, the nuclear-sourced device is non-adjustable for pavement area and depth, requires long time for, and is very heavy and difficult to maneuver. Furthermore, the nuclear-sourced device is also very expensive, at least in part due to the nuclear material of the nuclear-sourced device. Additionally, these nuclear density devices need to be constantly correlated to core densities that are taken from the same location as was nuclear gauge tested. This correlation should be done for each different mix that might be used. These steps are of course timely and cost consuming, and thus make use of these nuclear devices undesirable.
Another conventional pavement density indicator device is set forth in U.S. Pat. No. 5,900,736 assigned to TransTech Systems. The TransTech System pavement density indicator device is a non-nuclear, asphalt density measuring device. The TransTech System pavement density indicator device appears to be based on electric field or capacitance.
Recently, current developments in paving technology have allowed pavement to be applied in thinner layers, as compared to the pavement layers applied in the past. This thinner pavement reduces the amount of pavement that can be bored from rolled pavement, for example for a test core (described hereinafter). Accordingly, a need exists for a reliable, convenient pavement density, compaction, and segregation degree determining device, in which the device functions with desired results in which the top area of the pavement does not adversely influence the operation of an apparatus and method to analyze density and segregation of a material, especially if used on pavement, which is applied in thick or thin layers.
Further, the application of pavement may vary dependent on the pavement""s underlying base structure, thus resulting in differing depths, areas, shapes, and volumes of the pavement. Of course, it is desirable to determine the density, compaction, and segregation degree of such pavement. Therefore, it is desirable to provide a pavement density, compaction, and segregation degree determining device that is capable of pavement density measurement at differing depths, areas, shapes, and volumes of the pavement.
Furthermore, the operation of conventional apparatus that attempt to measure the density, compaction, and segregation degree of pavement is often slow and requires complicated operations for appropriate device functionality. This lack of speed is often adverse to the determination of pavement density and compaction. Thus, the measure of density, compaction, and segregation degree is typically a tedious and drawn-out process that slows down the ultimate pavement application operation. Accordingly, a need exists to provide an asphalt pavement density analyzer or convenient pavement density, compaction, and segregation degree determining device that can determine pavement density in a faster, more convenient process than those currently available.
Yet another potential disadvantage of the conventional pavement density indicator devices may be found in an inability to move to various configurations, such as in shape and area. The conventional devices often do not permit movement or alteration of the sensing area, and are not configured to readily permit the pavement density indicator device to be moved to determine density and compaction. Accordingly, a need exists for a pavement density indicator device that can determine pavement density in particular configurations of pavement.
The invention is directed to an apparatus to analyze density and segregation of a material. The material analyzing apparatus comprises an analyzer body that comprises a generally insulative material casing; a material analyzing circuitry that includes a transmitter, a receiver, and a control; an antenna system that comprises a transmitting antenna, a receiving antenna, and a ground layer; a coupling structure that couples the antenna system to the material analyzing circuitry. The transmitter of the material analyzing circuitry generates a VHF electromagnetic wave signal that is adapted to be sent by the transmitting antenna and directed into the material to be analyzed. The receiving antenna receiving any returned signal from the material and sent to the receiver and to the control. The control then able to analyze the signal for material characteristics.
Further, the invention sets forth a material analyzing apparatus. The material analyzing apparatus comprises an analyzer body that comprises a generally insulative material casing; a material analyzing circuitry that includes comprising a transmitter, a receiver, and a control; an antenna system that comprises a transmitting antenna, a receiving antenna, and a ground layer; a coupling structure that couples the antenna system to the material analyzing circuitry. The transmitter of the material analyzing circuitry generates a VHF electromagnetic wave signal that is adapted to be sent by the transmitting antenna and directed into the material to be analyzed. The receiving antenna receiving any returned signal from the material and sent to the receiver and to the control. The control then able to analyze the signal for material characteristics. The material characteristics including at least one of density and material segregation.
The invention is directed to an apparatus to analyze density and segregation of a material. The material analyzing apparatus comprises an analyzer body that comprises a generally insulative material casing; a material analyzing circuitry that includes comprising a transmitter, a receiver, and a control; an antenna system that comprises a transmitting antenna, a receiving antenna, and a ground layer; a coupling structure that couples the antenna system to the material analyzing circuitry. The transmitter of the material analyzing circuitry generates a VHF electromagnetic wave signal that is adapted to be sent by the transmitting antenna and directed into the material to be analyzed. The receiving antenna receiving any returned signal from the material and sent to the receiver and to the control. The control then able to analyze the signal for material characteristics. Density of the material can be linearly related to a returned signal. The control can determine density D being generally equal to a measured returned voltage V times a constant slope m, plus an offset b, in accordance with:
D=mxc3x97V+b. 
The invention is directed to an apparatus to analyze density and segregation of a material. The material analyzing apparatus comprises an analyzer body that comprises a generally insulative material casing; a material analyzing circuitry that includes a transmitter, a receiver, and a control; an antenna system that comprises a transmitting antenna, a receiving antenna, and a ground layer; a coupling structure that couples the antenna system to the material analyzing circuitry. The transmitter of the material analyzing circuitry generates a VHF electromagnetic wave signal that is adapted to be sent by the transmitting antenna and directed into the material to be analyzed. The receiving antenna receiving any returned signal from the material and sent to the receiver and to the control. The control then able to analyze the signal for material characteristics. The control then able to analyze the signal for material characteristics, the material segregation of   SL  =      k    ⁢                  ∫        s1        s2            ⁢              "LeftBracketingBar"                              Δρ            /            Δ                    ⁢                      xe2x80x83                    ⁢          s                "RightBracketingBar"            
where k is a constant, xcfx81 is pavement density and s is distance across a surface.
A further aspect of the invention provides a method for analyzing a material. The method comprises providing an analyzer body, the analyzer body comprising a generally insulative material casing; providing material analyzing circuitry, the material analyzing circuitry comprising a transmitter, a receiver, and a control; providing an antenna system, the antenna system comprising a transmitting antenna, a receiving antenna, and a ground layer; coupling antenna system to the material analyzing circuitry; and generating a VHF electromagnetic wave signal; transmitting the VHF electromagnetic wave signal by the transmitting antenna; directing the signal to be analyzed; receiving any returned signal from the material; sending the returned signal to the receiver and control; and analyzing the signal for material characteristics.
A material analyzing apparatus for measuring material segregation. The apparatus comprising analyzer body, the analyzer body comprising a generally insulative material casing; material analyzing circuitry, the material analyzing circuitry comprising a transmitter, a receiver, and a control, an antenna system, the antenna system comprising a transmitting antenna, a receiving antenna, and a ground layer; a coupling structure that couples the antenna system to the material analyzing circuitry. The transmitter of the material analyzing circuitry generates a VHF electromagnetic wave signal, the VHF electromagnetic wave signal being adapted to be sent by the transmitting antenna, being directed into the material to be analyzed, the receiving antenna receiving any returned signal from the material and then sent to the receiver and to the control, the control then able to analyze the signal for material characteristics, the material segregation (Seg or Segregation Level) being determined by: Seg=constantxc3x97SD+offset, where SD is the standard deviation of measurements.
A further aspect of the invention provides a method for analyzing a material. The method comprises providing an analyzer body, the analyzer body comprising a generally insulative material casing; providing material analyzing circuitry, the material analyzing circuitry comprising a transmitter, a receiver, and a control; providing an antenna system, the antenna system comprising a transmitting antenna, a receiving antenna, and a ground layer; coupling antenna system to the material analyzing circuitry; and generating a VHF electromagnetic wave signal; transmitting the VHF electromagnetic wave signal by the transmitting antenna; directing the signal to be analyzed; receiving any returned signal from the material; sending the returned signal to the receiver and control; and analyzing the signal for material characteristics. The step of analyzing the signal for material segregation characteristics can be determined by   SL  =      k    ⁢                  ∫        s1        s2            ⁢              "LeftBracketingBar"                              Δρ            /            Δ                    ⁢                      xe2x80x83                    ⁢          s                "RightBracketingBar"            
where k is a constant, xcfx81 is pavement density and s is distance across a surface.
A further aspect of the invention provides a method for analyzing a material. The method comprises providing an analyzer body, the analyzer body comprising a generally insulative material casing; providing material analyzing circuitry, the material analyzing circuitry comprising a transmitter, a receiver, and a control; providing an antenna system, the antenna system comprising a transmitting antenna, a receiving antenna, and a ground layer; coupling antenna system to the material analyzing circuitry; and generating a VHF electromagnetic wave signal; transmitting the VHF electromagnetic wave signal by the transmitting antenna; directing the signal to be analyzed; receiving any returned signal from the material; sending the returned signal to the receiver and control; and analyzing the signal for material characteristics. the density of the material being linearly related to a returned signal, and determining density D being generally equal to a measured returned voltage V times a constant slope m, plus an offset b, in accordance with:
D=mxc3x97V+b. 
A further aspect of the invention provides a material analyzing apparatus for measuring material segregation. The apparatus comprises an analyzer body that comprises a generally insulative material casing; material analyzing circuitry that comprises a transmitter, a receiver, and a control; an antenna system, in which the antenna system comprises a transmitting antenna, a receiving antenna, and a ground layer; a coupling structure that couples the antenna system to the material analyzing circuitry. The transmitter of the material analyzing circuitry generates a VHF electromagnetic wave signal. The VHF electromagnetic wave signal being adapted to be sent by the transmitting antenna, and is directed into the material to be analyzed. The receiving antenna receiving any returned signal from the material and then sending same to the receiver and to the control. The control is then able to analyze the signal for material characteristics. The material segregation (Seg) being determined by Seg=constantxc3x97SD+offset, where SD is the standard deviation of measurements.
A yet further aspect of the invention sets forth a method for measuring material segregation. The method comprises providing an analyzer body comprising a generally insulative material casing; providing material analyzing circuitry comprising a transmitter, a receiver, and a control; providing an antenna system comprising a transmitting antenna, a receiving antenna, and a ground layer; coupling the antenna system to the material analyzing circuitry; generating a VHF electromagnetic wave signal; transmitting the VHF electromagnetic wave signal by the transmitting antenna; directing the signal to be analyzed; receiving any returned signal from the material; sending the returned signal to the receiver and control; and analyzing the signal for material segregation characteristics. The determining material segregation (Seg) is by Seg=constantxc3x97SD+offset, where SD is the standard deviation of measurements.